Avalanche Forecast

Archived

Jan 18th, 2018–Jan 19th, 2018

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis.

New snow and strong winds are initiating an avalanche cycle in the alpine. The current snowpack is complex so choose conservative terrain as the snowpack settles.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Friday

Weather Forecast

A few more cm's of snow is likely to fall overnight with continued moderate to strong winds out of the SW. On Friday we are expecting snowfalls to diminsh and winds to calm down. Freezing levels are foreast to drop back to 1500m with daytime highs around -11C.

Avalanche Summary

Winds and new snow was triggering a few slabs out of lee and cross-loaded features up to sz 2. We suspect there was more slabs out but conditions were obscured throughout the day and visibility was limited.

Snowpack Summary

10-20cm of new snow fell over the past 24hrs with moderate westerly winds at treeline and suspected higher winds in the alpine. This new snow is also now burying the previous windslabs that developed last week as well as a new layer of surface hoar that was being found up to treeline. Two additional layers in the upper snowpack are still producing concerns. The Jan 6th down 40cm (moderate results) and the Dec 15th down 60-80cm (producing hard results). Despite a lack of recent activity on these interfaces they are still in our mind and we are treating she;tered treeline areas cautiously. Watch for new windslabs and storm slabs building along N and E aspects at treeline and above.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.